1 / 31

Atmospheric muons in neutrino detector AMANDA

Dmitry Chirkin. Atmospheric muons in neutrino detector AMANDA. chirkin@physics.berkeley.edu University of California at Berkeley, Berkeley, CA 94720, USA. LBL, July 8 2004. South Pole. AMANDA-II. Particles observed by AMANDA-II. Down-going muons observed by AMANDA-II.

isolde
Télécharger la présentation

Atmospheric muons in neutrino detector AMANDA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dmitry Chirkin Atmospheric muons in neutrino detector AMANDA chirkin@physics.berkeley.edu University of California at Berkeley, Berkeley, CA 94720, USA LBL, July 8 2004

  2. South Pole AMANDA-II

  3. Particles observed by AMANDA-II

  4. Down-going muons observed by AMANDA-II

  5. Introduction to AMANDA-II Monte Carlo simulation

  6. Brief description of the simulation

  7. Air shower generator CORSIKA settings

  8. Muon propagator (MMC)

  9. Muon propagator (MMC) settings: ph-nu settings photoproduction DIS Q2 soft hard 1 GeV2 Abramowicz Levin Levy Maor Bezrukov-Bugaev Butkevich-Mikheyev BB 1981 2002 1991 1997 ZEUS 94 Nuclear effects BB + Hard 03 Bugaev Shlepin Kokoulin 99 Dutta Smirnov

  10. Properties of muon energy spectrum at the depth of the AMANDA-II detector • Simple 1d model • Full CORSIKA+MMC simulation • Observed muon flux calculation • Fits to the Nch distribution • Results for cosmic ray flux • Calculation of muon flux on the surface • Energy range of result validity • Muon multiplicity effect on the results

  11. Detailed description of the energy loss model • Etop < 100 GeV: • muon stops inside detector • up to ~ 500 GeV losses • are continuous, • indep. of Etop • after ~ 1TeV losses • are prop. to Etop, • slope decreases • at small energies muon • energy losses are well • defined (deterministic) • since they are mostly • continuous

  12. Fits to the Nch distribution To extract the features of the Nch distribution, it was fit with , with x=Nch , where x=log10(Nch)

  13. Noise cleaning in the Nch distribution • average noise l ~4 • n is high (n~40>> l) • a and b are slowly • varying functions • of n • b is small (b~0.1) It is sufficient to shift the fit by l to correct Nch for noise

  14. Observed muon flux calculation muon signal = OM signal – noise + missed signal raw 1-Pt = (1-Ps) (1-Pn) calibrated Nmuon sig. = Ps Nall • this works for: • single OM • several OMs

  15. Observed muon flux calculation: layered model OM X efficiency: muon number at X: To get noise-corrected numbers for set intersections use

  16. Observed muon flux calculation: improved layered model for the total number of events P(X) with muons seen at X: if 1 and 2 are very large then OM X’s effective sensitivity is X/P(X)

  17. Method 1 z [m] z [m]

  18. Method 2 normalization: z [m] z [m]

  19. Seasonal variations and detector configuration uncertainties spectral index correction Normalization (flux at 1 TeV) in spectral index correction coordinate transformation

  20. Results For QGSJET (only H component values are shown, for relative abundances taken from Wiebel-Sooth) method 1 Values shown are for DPMJET, HDPM, NEXUS, QGSJET, SIBYLL, VENUS interaction models, experimental data shown according to Wiebel-Sooth and Jorg Horandel

  21. Results method 1 method 2

  22. Fits to muon spectra

  23. Other muon spectra fits muon maximum energy spectrum All muon spectrum (SIBYLL)

  24. Muon spectrum results • muon vertical flux at 1 TeV: • 1.03 10-10 cm-2 sr-1 s-1 GeV-1 • errors: • ± 0.07 (primary flux) • 0.02 (ice) • 0.04 (atm) • 0.06 (conf) • ± 0.02 (HE int. model) • Total: 1.03 ± 0.07

  25. Observed energies of primaries and muons

  26. Why do different interaction models result in different flux?

  27. Observed muon multiplicity

  28. Conclusions • Developed method depends weakly on ice parameters or • detector configuration • Cosmic ray flux corrections for both spectral index and • normalization are obtained. For QGSJET, γ=2.70±0.02, • and Φ0=0.106 ±0.007 m-2sr-1s-1TeV-1 (for H component). • Spectral index for muons depends on the interaction • model and is 2.66±0.02 for QGSJET • Muon flux at 1 TeV appears to be independent of high- • energy interaction model and for vertical muons is • 1.03±0.07 10-10 cm-2sr-1s-1GeV-1. • QGSJET, VENUS and NEXUS results agree best with • other experiments, but QGSJET is by far the fastest. • Insufficient accuracy in the description of multi-muon • events is the likely cause for disagreement between HE • interaction models

  29. Fits to muon flux: corrected formula Simple formula: • Corrections: • cos* for curved atmosphere • muon energy losses • muon decay

  30. Nutrino fluxes

More Related